Can't See All Memory - CentOS 4.2

I am in the process of setting up some servers, IBM X360 rack servers. They are decked out with 16 gigs of memory and quad xeon processors per system. CentOS is only seeing 8 gigs of the 16. I checked the BIOS, and the BIOS is reporting 16 gigs of ECC Registered memory correctly.

I did some research and saw IBM recommending I use the EL Hugemem kernel, so I went out and tried that. Still the same results. Here's the current kernel information.

I went ahead and compiled a new kernel based off of the current config with a few changes and still the same issue. I compiled 2.6.17 with the same results. I verified that largemem was available and it was set for 64 gigs of memory.